African Journal of Laboratory Medicine最新文献

Background: All medical laboratories must participate in proficiency testing (PT) programmes to ensure high-quality results. Proficiency testing samples mimic clinical samples; however, PT programmes for detection of bacteria in blood products are not routinely performed due to unavailability of matrix-equivalent samples.

Objective: The aim of this study was to develop and test a matrix-equivalent PT programme using blood products as the basis matrix.

Methods: A prospective cross-sectional study was conducted from April 2021 until June 2021, using 52 blood products comprising 36 pooled platelet and 16 red blood cell products at the South African National Blood Service PT laboratory in Gauteng. Products were manipulated into matrix-equivalent PT samples by spiking 42 products with known bacterial strains at specific concentrations and treating the remaining 10 products with preserving fluid containing antibiotics. The level of agreement between the researcher results and participating laboratories' results was assessed.

Results: Of the prepared matrices, 568 out of 572 (99%) were stable for 30 days. Bacteria could correctly be identified in spiked samples for up to 23 days. Samples treated with preserving fluid remained negative until day 30. For spiked samples, an average of 98% agreement (153/156) was achieved between the three participating laboratories when compared with the researcher's results; 100% agreement was achieved for unspiked samples. The kappa scores obtained from all tested variables presented with scores between 0.856 and 1.000, and the p-value was < 0.001 throughout.

Conclusion: The developed PT matrix was therefore stable and suitable to be implemented in transfusion microbiology.

What this study adds: This study demonstrated that a stable microbiology PT programme using platelets and red blood cells can be developed for use on bacterial detection analysers and could help to close the gap presented by unavailability of a blood PT matrix for transfusion microbiology.

Background: Integrated testing, treatment and care are key strategies for addressing the dual burdens of tuberculosis and HIV. The GeneXpert instrument allows simultaneous HIV and tuberculosis testing, but its utilisation for integrated testing remains suboptimal.

Objective: The study determined the extent to which tuberculosis testing and HIV early infant detection (EID) were integrated on the GeneXpert platform, or the potential for integration at selected health facilities.

Methods: A mixed methods evaluation was conducted using retrospective secondary data analysis of laboratory records from 2017 to 2019, and semi-structured interviews. Data were collected between January 2020 and March 2020 in Lesotho.

Results: Forty-four health staff were interviewed across 13 health facilities: one regional, nine district, and three clinic level. Six were government facilities, six were mission hospitals, and one was a non-profit clinic. All facilities selected had at least one GeneXpert instrument used for tuberculosis or HIV testing; none included simultaneous testing for tuberculosis and HIV. In 2017, the average utilisation rate for the GeneXpert instrument for tuberculosis and EID testing was 63% and 24%, while in 2019, the average utilisation rate was 61% for tuberculosis testing and 27% for EID.

Conclusion: Except for three sites where the testing rates were high, utilisation rates were sufficiently low that all the HIV EID and tuberculosis tests undertaken in 2017 and 2019 could have been performed using only the instruments currently dedicated to tuberculosis testing. There is a missed opportunity for the integration of testing for tuberculosis and HIV on the GeneXpert instrument.

What this study adds: This study adds to the body of evidence on the need for integration of testing and highlights some practical and technical considerations for successful implementation of integrated tuberculosis and HIV testing.

Background: Coronavirus disease 2019 (COVID-19) is a worldwide public health concern for healthcare workers. About 80% of cases appear to be asymptomatic, and about 3% may experience hospitalisation and later die. Less than 20% of studies have looked at the positivity rate of asymptomatic individuals.

Objective: This study investigated the COVID-19 positivity rates among asymptomatic individuals during the second COVID-19 wave at one of Zambia's largest testing centre.

Methods: This was a retrospective cross-sectional study conducted on routine surveillance and laboratory data at the Tropical Diseases Research Centre COVID-19 laboratory in Ndola, Zambia, from 01 December 2020 to 31 March 2021. The study population was made up of persons that had tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection as a requirement for travel. Microsoft Excel was used to come up with an epidemiological curve of daily COVID-19 positive cases; proportions for gender were described using frequencies and percentages.

Results: A total of 11 144 asymptomatic individuals tested for SARS-CoV-2 were sampled for the study and 1781 (16.0%) returned positive results. The median age among those tested was 36 years (interquartile range: 29-46). Testing for COVID-19 peaked in the month of January 2021 (37.4%) and declined in March 2021 (21.0%). The epidemiological curve showed a combination of continuous and propagated point-source transmission.

Conclusion: The positivity rate of 16.0% among asymptomatic individuals was high and could imply continued community transmission, especially during January 2021 and February 2021. We recommend heightened testing for SARS-CoV-2 among asymptomatic individuals.

What this study adds: This study adds critical knowledge to the transmission of COVID-19 among asymptomatic travellers who are usually a key population in driving community infection. This knowledge is critical in instituting evidence-based interventions in the screening and management of travellers, and its control.

A novel coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in China in 2019 and later ignited a global pandemic. Contrary to expectations, the effect of the pandemic was not as devastating to Africa and its young population compared to the rest of the world. To provide insight into the possible reasons for the presumed immune sufficiency to coronavirus disease 2019 (COVID-19) in Africa, this review critically examines literature published from 2020 onwards on the dynamics of COVID-19 infection and immunity and how other prevalent infectious diseases in Africa might have influenced the outcome of COVID-19. Studies characterising the immune response in patients with COVID-19 show that the correlates of protection in infected individuals are T-cell responses against the SARS-CoV-2 spike protein and neutralising titres of immunoglobin G and immunoglobin A antibodies. In some other studies, substantial pre-existing T-cell reactivity to SARS-CoV-2 was detected in many people from diverse geographical locations without a history of exposure. Certain studies also suggest that innate immune memory, which offers protection against reinfection with the same or another pathogen, might influence the severity of COVID-19. In addition, an initial analysis of epidemiological data showed that COVID‑19 cases were not severe in some countries that implemented universal Bacillus Calmette-Guerin (BCG) vaccination policies, thus supporting the potential of BCG vaccination to boost innate immunity. The high burden of infectious diseases and the extensive vaccination campaigns previously conducted in Africa could have induced specific and non-specific protective immunity to infectious pathogens in Africans.

This study evaluated the performance of the Xpert Carba-R assay for detecting the five common carbapenemases in carbapenemase-producing organisms in Johannesburg, South Africa between April 2021 and September 2021. The assay demonstrated 98% sensitivity and 97% specificity. It was also able to detect all the carbapenemases in double carbapenemase producers, as well as carbapenemases in non-fermenter organisms. The Xpert Carba-R assay, therefore, allows the rapid (< 1 h) and accurate identification of the common carbapenemases in pure bacterial cultures and rectal swabs. This assay can aid in the timeous institution of appropriate treatment and infection prevention and control measures.

[This corrects the article DOI: 10.4102/ajlm.v11i1.1570.].

Background: Inappropriate testing remains a high healthcare cost driver. Tumour marker tests are more expensive than routine chemistry testing. Implementing test demand management systems like electronic gatekeeping (EGK) has reportedly decreased test requests.

Objective: This study aimed to describe the appropriateness of tumour marker tests, carcinoembryonic antigen, alpha foetal protein, prostate-specific antigen, carbohydrate antigen 19-9, cancer antigen 15-3, cancer antigen 125, and human chorionic gonadotropin, and determine the effectiveness of the EGK used in the public health sector in KwaZulu-Natal, South Africa.

Methods: Tumour marker test data for the KwaZulu-Natal province were extracted from the National Health Laboratory Service Central Data Warehouse for 01 January 2017 - 30 June 2017 (pre-EGK) and 01 January 2018 - 30 June 2018 (post-EGK implementation). Questionnaires were sent to the clinicians in the regional hospitals ordering the most tumour marker tests to assess ordering practices. In addition, we assessed monthly rejection reports to determine the effect of the EGK.

Results: The EGK minimally reduced tumour marker requests or associated costs (1.4% average EGK rejection rate). An overall 18% increase in the tumour marker tests occurred in 2018. The data suggest inappropriate tumour marker test utilisation, particularly for screening.

Conclusion: The introduction of EGK as a test demand management had little impact on tumour marker test requests and costs. Continuous education and reiteration of indications for tumour marker test use are required.

What this study adds: This study demonstrates the ineffectiveness of EGK in tumour marker orders, and provides some insight as to why these markers are being ordered, which is important in trying to decrease inappropriate ordering of these tests.

Background: Despite the tremendous progress made in advancing laboratory medicine in low- and middle-income countries (LMICs), inadequate quality management systems (QMSs) remain a problem and barrier to provision of reliable laboratory services in resource-limited settings. Therefore, it is useful to study the experience of medical laboratories in LMICs that have successfully implemented QMS.

Aim: This review identified key success factors (KSFs) for medical laboratories in LMICs implementing QMS in accordance with the International Organization for Standardization standard 15189 as a pathway to improving laboratory quality.

Methods: Applying Preferred Reporting Items for Systematic Reviews procedures, we conducted a targeted search of studies from LMICs published between 2012 and 2022 to identify KSFs. Thirty-two out of 952 references retrieved were considered relevant and included in this review. Grounded theory was used to extract key features of the included studies to derive KSFs.

Results: Ten KSFs for medical laboratories striving to implement QMS were identified and described. These KSFs were integrated to create a model of success for laboratory QMS implementation. The model consists of three underlying factors, namely preparing for change, resource availability, and effective project management, each comprising three separate KSFs. Institutional commitment was identified as the core of the model and is integral to ensuring the quality of laboratory services.

Conclusion: Laboratories planning to implement a QMS can benefit from understanding the KSFs demonstrated in this study as this would help them to identify the necessary changes to implement and set realistic expectations about the outcomes of QMS implementation.

Background: The Stepwise Laboratory Improvement Process Towards Accreditation (SLIPTA) helps prepare laboratories in low- and middle-income countries to achieve international accreditation aligned with the ISO 15189:2012 standards. Accreditation by the Joint Commission International (JCI) is among the highest sought by hospitals worldwide. While the readiness of laboratories with a five-star SLIPTA score to undergo ISO 15189:2012 accreditation was recently assessed, the compliance of the SLIPTA checklist with JCI is still unknown.

Objective: The study evaluated the SLIPTA checklist's utility in assessing laboratories to meet the JCI standards.

Methods: We conducted a detailed gap analysis between SLIPTA and JCI laboratory standards from January 2021 to January 2022. We cross-matched the JCI standard requirements to SLIPTA clauses and categorised each standard into 'met', 'partially met', and 'not met'. We highlighted similarities, discrepancies, and improvement areas.

Results: A total of 109 JCI standards were included. The SLIPTA checklist completely met 61 standards, partially met four, but did not meet 44. The unmet JCI standards focused on the quality planning, control, and improvement sections. Healthcare organisation management and quality control processes, including selecting an accredited reference laboratory, collecting quality management data, creating of post-analytical policies and procedures, and validating monitoring systems, constitute the basis of this preparation.

Conclusion: The SLIPTA checklist covers major quality management system elements of the JCI standards for laboratories. However, some components should be addressed to assure readiness for JCI accreditation.

What this study adds: This study identified additional areas not covered by the SLIPTA checklist that are required for JCI accreditation.